System and method for D2D resource allocation

Abstract

When at least one of device-to-device UEs in connections of a group of D2D UEs is outside of the coverage area of mobile network of an access point, an information exchange mechanism established directly between the D2D UEs, without involving a third party, is provided. A resource allocation method for a device-to-device (D2D) communication link between two or more D2D user equipments (UEs) in a mobile communication network is provided according to an example. The method includes a first D2D UE indicating resource allocation information for the D2D communication link in a resource allocation message, wherein the resource allocation message is mapped into a resource allocation format; wherein the resource allocation format comprises one or more format flags; wherein one or more resource allocation messages are differentiated in the resource allocation format in accordance to the one or more format flags; and the first D2D UE transmitting the resource allocation format in a Physical Sidelink Control Channel (PSCCH) to one or more additional D2D UEs.

What is claimed is: 
     
       1. A method for communicating a resource allocation for a device-to-device (D2D) communication link between two or more user equipments (UEs) in a mobile communication network, the method comprising:
 identifying one or more Sidelink Control Information (SCI) message types each having a respective resource allocation format, wherein each message type comprises one or more format flags indicating the respective resource allocation format; 
 for each of the SCI message types, determining a length of a longest message of that type, 
 obtaining a first SCI message having a first type; 
 adjusting a length of the first SCI message based on the determined length of the longest SCI message of the first type; and 
 transmitting the adjusted first SCI message by a first UE in a Physical Sidelink Control Channel (PSCCH) to one or more second UEs for establishing the D2D communication link. 
 
     
     
       2. The method of  claim 1 , wherein the resource allocation format comprises only one format flag, and the only one format flag is mapped to all messages types needed for the communicating the resource allocation for the D2D communication link. 
     
     
       3. The method of  claim 1 , further comprising:
 establishing, by the first UE, a dedicated control channel between the first UE and the one or more second UEs according to the resource allocation information, wherein the dedicated control channel is used for communicating only control information between the first UE and the one or more second UEs. 
 
     
     
       4. The method of  claim 1 , wherein the one or more SCI messages are encoded according to the respective resource allocation format. 
     
     
       5. The method of  claim 1 , further comprising:
 determining that the length of the first SCI message is less than the predetermined length of the longest SCI message of the first type and, based thereon, 
 appending one or more dummy bits to the first SCI so that the size of the first SCI equals the length of the longest message of the first type. 
 
     
     
       6. The method of  claim 5 , wherein the dummy bit is zero. 
     
     
       7. The method of  claim 1 , further comprising:
 transmitting, in the first SCI message, sidelink scheduling information for one destination ID of the one or more second UEs. 
 
     
     
       8. The method of  claim 1 , wherein the resource allocation format is at least one of the following, format 0, format 1, format 2 or format 0-ext. 
     
     
       9. The method of  claim 1 , wherein an SCI message comprises resource allocation information which is at least one of the following,
 scheduling of the share channel for broadcast, scheduling of the share channel for unicast, scheduling of the share channel for both broadcast and unicast, or transmitting of feedback information. 
 
     
     
       10. The method of  claim 1 , further comprising:
 allocating at least one resource block of a sub-frame for transmitting the first SCI message to the one or more second UEs, wherein the sub-frame is a sub-frame of an uplink frame. 
 
     
     
       11. A device-to-device (D2D) user equipment (UE) comprising:
 a memory storing instructions; and 
 a processor coupled to the memory, wherein when the instructions are executed by the processor, the UE is configured to: 
 identify one or more Sidelink Control Information (SCI) message types each having a respective resource allocation format, wherein each message type comprises one or more format flags indicating the respective resource allocation format; 
 for each of the SCI message types, determine a length of a longest message of that type, 
 obtain a first SCI message having a first type; 
 adjust a length of the first SCI message based on the determined length of the longest SCI message of the first type; 
 and 
 transmit the adjusted first SCI message by a first UE in a Physical Sidelink Control Channel (PSCCH) to one or more second UEs for establishing the D2D communication link. 
 
     
     
       12. The D2D UE of  claim 11 , wherein the resource allocation format comprises only one format flag, and the only one format flag is mapped to all resource allocation messages types needed for the communicating the resource allocation for the D2D communication link. 
     
     
       13. The D2D UE of  claim 11  further configured to:
 establish by the first UE, a dedicated control channel between the first UE and the one or more second UEs according to resource allocation information, wherein the dedicated control channel is used for communicating only control information between the first UE and the one or more second UEs. 
 
     
     
       14. The D2D UE of  claim 11 , wherein the one or more SCI messages are encoded according to the respective resource allocation format; and
 determining that the length of the first SCI message is less than the predetermined length of the longest SCI message of the first type and, based thereon, 
 appending one or more dummy bits to the first SCI so that the size of the first SCI equals the length of the longest message of the first type. 
 
     
     
       15. The D2D UE of  claim 14 , wherein the dummy bit is zero. 
     
     
       16. The D2D UE of  claim 11 , wherein in the first SCI message transmits sidelink scheduling information for one destination ID of the one or more second UEs. 
     
     
       17. The D2D UE of  claim 11 , wherein the the first UE is further configured to allocate at least one resource block of a sub-frame for transmitting the first SCI message to the one or more second UEs, wherein the sub-frame is a sub-frame of an uplink frame.